Pump



Patented Dec. e, i941 PEM? Livio Goldschmied, Trieste, Italy Application May 14, 1940, Serial N0."3'35,063 lln Italy May 15, 1939 (Cl. S-105) 2 Claims.

This invention relates to pumps and more particularly to an improved Amulti-stage extraction pump of the centrifugal type.

In accordance with an illustrative embodiment of the present invention, the pump includes a generally spiral inlet chamber, into Fig. 2 is a longitudinal sectional view taken along line 2--2 of Fig. 1; and

which the uid is drawn peripherally and passes into a first stage impeller in an inward direction and from thence axially into a second stage or principal impeller which forces the fluid inan outward direction into a spiral outlet chamber fromv which the uid is discharged peripherally.

The inlet chamber is so shaped and :dimensioned that the fluid velocity is substantially uniform and the pressure loss is relatively low.

The inlet chamber and first stage impeller are so designed that the fluid is supplied to the second stage impeller substantially without cavitation. Both impellers are mounted on a single overhanging shaft which is journaled externally of the chambers and thus there are no bearings in contact with the iiuid. The impellers are in immediately adjacent relation and the pump casing is so shaped that the pump is very compact in construction.

An object of the present invention is the provision of a highly emcient pump of the type hereinbefore referred to Ain which the iluid iiows smoothly through the casing and `there is a minimum of interference and cavitation.

Another object of the invention is the provision A of a pump which is very compact and eilicient as to space required for installation of the pump.

Still another object of the invention is the provision of a pump of the multi-stage type wherein the impellers are so mounted that there are no bearings in contact with the uid in the pump.

Various other features and advantagesof the invention will be apparent from the following particular description and from van inspection of the .accompanying drawing.

Although the novel features which are believed to be characteristic of this inventionwill be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it maybe carried out, may be better understood by referring to the `following description taken in connection with the accompanying drawing forming a part hereof,in which Fig. 1`is a, vertical cross-sectional view taken axially through one form'of pump constructed *n accordance with the inventiom' 3 is a longitudinal cross-sectional View taken along line 3-3 of Fig. 1.

In the following description and in the claims,

various details will be identied by specic' names for convenience, but they are intended tov which may be constituted by a lsingle member..

or a plurality of members, suitably secured together. 'I'he casing l is formed to define an inlet chamber 2 and. outlet chamber 3. The inlet chamber 2 is of spiral shape which decreases in eifective cross-sectional area inwardlyv from a peripherally located'intake opening. The outlet chamber 3 is also of spiralform whiehpreferably increases in cross-sectional area outwardly toward a discharge opening peripherally located at the lo'wer portion of the same side of the casing as the intake opening. The inlet chamber 2 and the outlet chamber 3 are separated by a partition or wall 4 which has an opening 5 therethrough located axially of the pump to provide communication between the chambers.

An opening 6 is formed in the side Wall of the casing adjacent the outlet chamber 3 to permit the insertion of the impellers hereinafter described, which opening preferably Ais closed by a closure plate '1 havingy a seal 8 associated therewith. Y

Rotatably -mounted centrally of the inlet chamber 2 and extending into the opening 5, is a first stage impeller 9 having suitably shaped and arranged blades I which cause the iluid'to be drawn inwardly from the inlet chamber 2 'toward the axis of the impeller. The impeller 9 is carried on a shaft Il extending through the end plate 1 and terminating within the inlet chamber 2, a suitable stuing box l2 being provided in the end plate 1. Theshaft Il is journaled in a bearing or bearings (not shown) located externally of the casing I and .thus the bearings are not in contact with the uid in the pump.

Also carried on the shaft H for rotation therewith is-a second stage impeller I3 disposed immediately adjacent the first stageimpeller 9 and smoothly from the iirst to the second impeller. Thesecond stage impeller I3 is an out-now impeller and has blades I4 of suitable'shape and arrangement which hurl the fluid outwardly by centrifugal force and cause it to ow in a spiral direction along the outlet chamber 3. The rst stage impeller 9 has a substantially smaller external diameter than the second stage impeller I3.

The portion ofthe outlet chamber 3 which opening is connected to a suitable intakepipe (not shown) `and the pump is suitably primed. Upon rotation of the shaft, the pump draws fluid into the inlet chamber 2 and thefluid flows in a spiral direction in the inlet chamber 2 and inwardly into the first stage impeller 3. 'I'he iiuid is forced in an axial direction through the impeller 9 and into the impeller I3. The impeller I3 forces the fluid outwardly by centrifugal force into the outlet chamber 3 from which the fluid is expelled through the outlet opening.

The first stage impeller accomplishes only a small proportion of the work to be done by the pump and the principal work is done by the secondstage impeller.

Since the inlet opening and the inlet chamber are relatively large and are shaped to provide a constant uid velocity, the loss of pressure in the inlet chamber is relatively low and the eillciency of the pump, therefore, is relatively high. Moreover, the iiuid travels in a generally spiral path continuously throughout the casing with a minimum of change 'in direction and no abrupt change; this further contributes to the high efficiency of operation. In addition, the external friction of the impellers is relatively low.

Olwing to the construction of the casing and particularly the arrangement; o1' chambers, the

v of lesser effective overall axial length of the relatively small for any particular size of pump. Because of the efficiency of the pump, the impellers can be made relatively small and accordingly, light in weight, thus also permitting a compact and eilicient construction. Moreover, owing to the small size of the impellers, an overhung mounting of the'impellers on the shaft can be employed, thus avoiding the necessity for internal bearings.

If desired, one or more additional impellers may be provided, which impellers operate as centrifugal impellers, in a manner similar to the second stage impeller.

While certain novel features of the invention have been disclosed herein, and are pointed out in thev annexed claims, it Will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. A multi-stage pump of the centrifugal type comprising a casing defining a generally spiral inlet chamber having a peripherally located inlet opening and a cross-sectional area and axially displaced from said in let chamber, said chambers being ldefined in part by a partition converging inwardly in a direction toward said inlet'chamber.

2. A multi-stage pump of the centrifugal type comprising a unitary housing member dening inlet and outlet chambers and aI central communication passage therebetween, an opening in anexterior end wall of said housing adjacent said 'l outlet chamber, an inwardly concave end plate closing said opening, a rst impeller in said inlet chamber, a second` impeller in said outlet chamber complementary in shape to said end plate, and a. shaft extending through said end plate and into said inlet chamber and vcarrying said impellers for rotation in said chambers respectively.

LrvIo GOLDSCHMID.

pump may be made generally spiral outlet chamber 

